In evolution of fabricating semiconductor, the integration level of IC always obeys the Moore's law. However, the Moore's law confronts a real challenge after the feature size of IC has evolved from 65 nm to 40 nm or even 28 nm, because of the physical limit, equipment cost and system complexity. In order to achieve the highest space efficiency, the semiconductor technology has proceeded to the 3D high-density stacking wiring technology.
Among the 3D high-density stacking wiring technology, the TSV (Through-Silicon Via) technology is a critical technology, which uses vertical conduction to implement electric connection among stacked chips, whereby the integration level and performance is effectively promoted with lower cost, and whereby a high-performance chip can be fabricated in a smaller size.
For example, a U.S. Patent Publication No. 20030092256 disclosed a “Method of Manufacturing Semiconductor and Its Device”, which comprises steps of: forming first holes not penetrating a support side semiconductor substrate on one face of the support side semiconductor substrate; forming a ground insulating film; forming primary connection plugs by charging copper into the first holes; forming a semiconductor film on one face side of the support side semiconductor substrate via an intermediate insulating film; forming elements on the semiconductor film; exposing bottom faces of the primary connection plugs by polishing the other face of the support side semiconductor substrate; forming second holes extending from the element forming face of the semiconductor film to the primary connection plugs; and forming auxiliary connection plugs for electrically connecting the elements with the primary connection plugs by charging copper into the second holes.
However, the conventional TSV technology involves many steps of photomask fabrication, photolithography, sputtering, electroplating, etc., which are complicated and time-consuming, and thus which has more instability factors in the fabrication process and needs higher fabrication cost.